From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753494AbbDXN2c (ORCPT ); Fri, 24 Apr 2015 09:28:32 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:23577 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752331AbbDXN2a (ORCPT ); Fri, 24 Apr 2015 09:28:30 -0400 Date: Fri, 24 Apr 2015 09:27:49 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: xen-devel@lists.xensource.com, baozich@gmail.com, David Vrabel , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] xen: Add __GFP_DMA flag when xen_swiotlb_init gets free pages on ARM Message-ID: <20150424132749.GA9192@l.oracle.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 24, 2015 at 10:16:40AM +0100, Stefano Stabellini wrote: > Make sure that xen_swiotlb_init allocates buffers that are DMA capable > when at least one memblock is available below 4G. Otherwise we assume > that all devices on the SoC can cope with >4G addresses. We do this on > ARM and ARM64, where dom0 is mapped 1:1, so pfn == mfn in this case. > > No functional changes on x86. > > From: Chen Baozi > > Signed-off-by: Chen Baozi > Signed-off-by: Stefano Stabellini > Tested-by: Chen Baozi Acked-by: Konrad Rzeszutek Wilk > > diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h > index 2f7e6ff..0b579b2 100644 > --- a/arch/arm/include/asm/xen/page.h > +++ b/arch/arm/include/asm/xen/page.h > @@ -110,5 +110,6 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) > bool xen_arch_need_swiotlb(struct device *dev, > unsigned long pfn, > unsigned long mfn); > +unsigned long xen_get_swiotlb_free_pages(unsigned int order); > > #endif /* _ASM_ARM_XEN_PAGE_H */ > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c > index 793551d..4983250 100644 > --- a/arch/arm/xen/mm.c > +++ b/arch/arm/xen/mm.c > @@ -4,6 +4,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -21,6 +22,20 @@ > #include > #include > > +unsigned long xen_get_swiotlb_free_pages(unsigned int order) > +{ > + struct memblock_region *reg; > + gfp_t flags = __GFP_NOWARN; > + > + for_each_memblock(memory, reg) { > + if (reg->base < (phys_addr_t)0xffffffff) { > + flags |= __GFP_DMA; > + break; > + } > + } > + return __get_free_pages(flags, order); > +} > + > enum dma_cache_op { > DMA_UNMAP, > DMA_MAP, > diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h > index 358dcd3..c44a5d5 100644 > --- a/arch/x86/include/asm/xen/page.h > +++ b/arch/x86/include/asm/xen/page.h > @@ -269,4 +269,9 @@ static inline bool xen_arch_need_swiotlb(struct device *dev, > return false; > } > > +static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order) > +{ > + return __get_free_pages(__GFP_NOWARN, order); > +} > + > #endif /* _ASM_X86_XEN_PAGE_H */ > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > index 810ad41..4c54932 100644 > --- a/drivers/xen/swiotlb-xen.c > +++ b/drivers/xen/swiotlb-xen.c > @@ -235,7 +235,7 @@ retry: > #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT)) > #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) > while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { > - xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order); > + xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order); > if (xen_io_tlb_start) > break; > order--;